Known in the present state of the art are impression tonometers and tonographs that measure intraocular pressure in conventional units, one such unit corresponding to a diaplacement of 50 .mu.m. The readings taken in conventional units are translated into millimeters of mercury by means of special conversion tables or through the use of a computing device, which is more convenient in medical practice (cf. SU A 135,583, SU A 294,608, SU A 1,044,272). However, additional computation extends the patient's servicing time, while incorporation of computing devices sophisticates construction of such tonometers.
In addition, the aforesaid conversion and computation involves errors due to stepwise arranged numerical data in special conversion tables so that the data increments substantially increase within the domain of low values of the measured pressure expressed in conventional units.
The technical solution closest to the present invention is a high-frequency tonometer for measuring and recording the intraocular pressure, comprising a frequency-output linear-motion transducer, said motions corresponding to intraocular pressure expressed in conventional units, and a recording instrument. The transducer incorporates a plunger which is traversable with respect to the casing so as to change its position relative to the inductors accommodated in the transducer casing. The transducer output frequency is proportional to the length of the plunger travel with respect to the transducer casing and is converted into a d.c. signal which is taken down by the recording instrument. Then the pressure measured in the conventional units is represented in millimeters of mercury by the conversion technique described above (cf. SU A 119,651).
However, making use of a special conversion table involves interpolation of the tabulated numerical data, while application of a special computing unit complicates substantially the entire tonometer. Moreover, the initial section, according to which intraocular pressure is as a rule estimated, is featured in a majority of cases by the widely variable displacement values, which are to be averaged. The data averaging procedure is usually performed by the operator in the course of data processing, which affects adversely the effectiveness and accuracy of measurements.
The invention is aimed at the provision of an ophthalmotonometer which would be capable of measuring intraocular pressure directly in millimeters of mercury.